szabo



Jan. 24, 1956 F. w. SZABO 2,731,952

FLUID SYSTEM HAVING SELECTABLE FLUID OPERATING PRESSURES Filed Sept. 26,1951 V vwuw 27 23 2/ 39 m 0P V 20 w REG. 46 37 24 MESSUHE PRESSUREP031770 POSITION IN VEN TOR.

FERDINAND W. SZABO W M 1W/ W EXHAUST HIgJ POSITION i r i t United StatesPatent FLUID SYSTEM HAVING SELECTABLE FLUID OPERATING PRESSURESFerdinand W. Szabo, Maple Heights, Ohio Application September 26, 1951,Serial No. 248,431

4 Claims. (Cl. 121-38) My invention relates in general to control meansand more particularly to control means for controlling the flow of fluidfrom a pressure source and selectively ap plying high and low pressureto a chamber, such, for example, as a piston chamber for actuating achuck to hold a workpiece in a machine tool.

An object of my invention is the provision of applying selectively highand low pressure to a fluid actuating piston which controls the grip orforce in which a fluid chuck engages a workpiece.

Another object of my invention is the provision of applying low pressureto a piston chamber and then when it becomes desirable to apply highpressure, the fluid is admitted to the piston chamber through a by-passconduit which is in parallel with the pressure relief valve which admitslow pressure to the piston chamber.

Another object of my invention is the provision of momentarilyexhausting the fluid from the piston chamber as the control valve whichadmits high pressure to the chamber is actuated from open to closedposition.

Another object of my invention is the provision of exhausting the highpressure fluid from the piston chamber momentarily as the pressureadmitted to the piston chamber is transferred from a high pressure to alow pressure.

Another object of my invention is the provision of controlling the fluidactuating valves by electrical means.

Another object of my invention is the provision of providing in the highpressure control valve an exhaust valve means which momentarily exhauststhe high pressure within the piston chamber as the control valve ismoved from open to closed position.

Other objects and a fuller understanding of my invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawing, in which:

Figure 1 shows a diagrammatic illustration of a fluid control meansembodying the features of my invention;

Figure 2 is a modified form of the invention;

Figure 3 is a view of the control valve shown in Figure 2, butillustrated in an intermediate position; and

Figure 4 is another view of the control valve shown in Figure 2, beingshown in the closed position.

With reference to Figure l of the drawing, 1 illustrate a fluid operatedchuck adapted to hold a workpiece 11. The fluid operated chuck 10 may beof any conventional design as embodied in modern machine tools. Asillustrated, the fluid operated chuck 10 is actuated by a piston 13mounted in a cylinder 12 so that as fluid is admitted to the pistonchamber 14 the chuck 10 is actuated to a closed position; and as fluidis exhausted from the piston chamber 12, the spring 16 actuates thechuck to open position.

The admission of fluid to the piston chamber 14 and the exhaust of thefluid therefrom is controlled by a chuck control valve 15.

The conduit 20 represents the fluid supply source and the pressure towhich it is regulated is governed by a constant pressure regulatingvalve 21, whereby the fluid within the conduit 22 is of a constantpressure source depending upon the setting of the regulating valve 21.Fluid from the constant pressure source 22 flows through a conduit 23, apressure reducing valve 27, and conduits 24 and 25 to the chuck controlvalve 15 and then through a conduit 26 to the fluid piston chamber 14.The fluid conduits 23 and 24 may be regarded as first conduit means.Connected in parallel with the first conduit means is a by-pass conduitmeans comprising the conduits 30 and 31. Mounted in the conduit 31 is acontrol valve 32 which is actuated to open and closed positions by meansof a solenoid 33 and a spring 34. When the solenoid 33 is energized thecontrol valve 32 is actuated to open position, and when the solenoid isde-energized the spring 34 actuates the control valve to closedposition.

An exhaust valve 37 is connected in communication with the conduit 24,whereby when the exhaust valve is actuatedto open position the fluidwithin the piston chamber 14 is exhausted to atmosphere. The exhaustvalve 37 may be actuated to closed position by means of a spring 39actuated to open position by a solenoid 38. An electrical switch 40 isadapted to control the operation of the solenoids 33 and 38. The switch40 comprises a control arm 41 which is adapted to make contact with thecontacts 42 and 43. Means 44 designates a position.

In operation, when the control arm 41 is making contact with the contact42, current flows from the supply conductor 45 through the control arm41, the contact 42 and the winding of the solenoid 33 to the othersupply conductor 46. The circuit energizes the solenoid 33 and actuatesthe control valve 32 to its open position for admitting fluid under highpressure to the piston chamber 14. In the event that the operatordesires to reduce the pressure of the chuck force upon the workpiece 11,he actuates the control arm 41 to the contact 44. As the arm 41 swingsto the right in Figure 1, it makes intermediate contact with the slidingcontact 43 for energizing the solenoid 38 which momentarily actuates theexhaust valve 37 to its open position for exhausting air from the pistonchamber 14 to atmosphere. The amount that the pressure is reduced in thepiston chamber 14 is equal to a value comparable to the low pressureeffected by the pressure reducing valve 2'7. As the control arm leavesthe slide contact 43 and is moved to the contact 44, the solenoid 38 isde-energized and the spring 39 closes the exhaust valve 37, after whichthe pressure within the piston chamber 14 is maintained at a low valuedetermined by the setting of the pressure reducing valve 27. The lengthof the sliding contact 43 is such that enough time elapses to permit theexhaust valve 37 to drain the fluid from the piston chamber 14 to reducethe pressure to a low value.

Accordingly, I have disclosed in Figure l a control means forcontrolling the flow of fluid from a pressure source 22 and selectivelyapplying high and low pressure to the piston chamber 14 determined bythe setting of the regulator 21 and the pressure reducing valve 27.

in Figure 2 I show a modified form of the invention, in that thecomplete control is effected by a control valve 58 which is actuatedfrom open to closed position by means of a solenoid 51 and from closedto open position by a solenoid 52 governed, respectively, by the pushbuttons 53 and 54. In Figure 2 the control valve is illustrated in openposition and high pressure is admitted to the piston chamber 14.

In Figure 3 I show the control valve 54 in an intermediate exhaustposition, being the position in which the piston chamber 14 is in fluidcommunication with an exhaust conduit 59 through an exhaust valve cavity58. Accordingly, in Figure 3 the control valve is illustrated in theexhaust position. As the control valve 50 is further actuated in acounterclockwise direction to the low pressure position shown in Figure4, the exhaust valve cavity 58 is moved out of communication with theexhaust conduit 59 whereby the fluid can no longer be exhausted andwhereby the pressure applied to the piston chamber 14 is controlled bythe setting of the pressure reducing valve 27. Accordingly, in Figure 21 illustrate a fluid control valve for controlling the flow of fluidfrom a pressure source 22 and selectively applying high and low pressureto the piston chamber 14 whereby the pressure grip of the chucks of thejaw on the workpiece may be varied from a high to a low value toaccommodate the workpiece.

Although the invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. Control means for controlling flow of fluid from a pressure sourceand selectively applying high and low pressure to a chamber, saidcontrol means comprising first conduit means connecting said pressuresource to said chamber, said first conduit means comprising a fixedfluid path and a manually operated on-and-off valve in said fixed fluidpath, a pressure reducing valve in said first conduit means to admitfluid of a pressure lower than said pressure source to said chamberthrough said first conduit means, by-pass conduit means connected inparallel with said pressure reducing valve, a control valve in saidby-pass conduit means, electrical control means to actuate said controlvalve to open and closed positions, said control valve in said openposition admitting fluid to said chamber of a pressure higher than thatadmitted to said chamber by said pressure reducing valve, exhaust meansunder control of said electrical control means and communicating withsaid chamber to momentarily exhaust fluid therefrom to reduce thepressure therein as said control valve is being actuated by saidelectrical control means from open to closed position, and saidelectrical control means comprising separately energized circuits toinsure that said exhaust means is open at a time when said control meansis closed, and manually operable contact means to separately energizesaid circuits.

2. Control means for controlling flow of fluid from a pressure sourceand selectively applying high and low pressure to a chamber, saidcontrol means comprising first conduit means connecting said pressuresource to said chamber, said first conduit means comprising a fixedfluid path and a manually operated on-and-off valve in said fixed fluidpath, a pressure reducing valve in said first conduit means to admitfluid of a pressure lower than said pressure source to said chamberthrough said first conduit means, by-pass conduit means connected inparallel with said pressure reducing valve, a control valve in saidby-pass conduit means, electrical control means to actuate said controlvalve to open and closed positions, said control valve in said openposition admitting fluid to said chamber of a pressure higher than thatadmitted to said chamber by said pressure reducing valve, exhaust valvemeans communicating with said chamber, means under control of saidelectrical control means to momentarily operate said exhaust valve meansto open position in said chamber to reduce the pressure as said controlvalve is being actuated by said control means from open to closedposition, and said electrical control means comprising separatelyenergized circuits to insure that said exhaust means is open at a timewhen said control means is closed, and manually operable contact meansto separately energize said circuits.

3. Control means for controlling flow of fluid from a pressure sourceand selectively applying high and low pressure to a chamber, saidcontrol means comprising first conduit means connecting said pressuresource to said chamber, said first conduit means comprising a fixedfluid path and a manually operated on-and-oflf valve in said fixed fluidpath, a pressure reducing valve in said first conduit means to admitfluid of a pressure lower than said pressure source to said chamberthrough said first conduit means, by-pass means connected in parallelwith said pressure reducing valve, a control valve in said by-passconduit means, electrical means to actuate said control valve to openand closed positions, said control valve in said open position admittingfluid to said chamber of a pressure higher than that admitted to saidchamber by said pressure reducing valve, exhaust valve meanscommunicating with said chamber, second electrical means to momentarilyoperate said exhaust valve means to open position in said chamber toreduce the pressure as said control valve is being actuated from open toclosed position, and first and second manually operable contact meansfor respectively controlling said electrical means and said secondelectrical means.

4. Control means for controlling flow of fluid from a pressure sourceand selectively applying high and low pressure to a cylinder having apiston defining a fluid chamber for actuating a chuck to hold aworkpiece, said control means comprising first conduit means connectingsaid pressure source to said chamber, said first conduit meanscomprising a fixed fiuid path and a manually operated on-and-oif valvein said fixed fluid path, a pressure reducing valve in said firstconduit means to admit fluid of a pressure lower than said pressuresource to said chamber through said first conduit means, by-pass conduitmeans connected in parallel with said pressure reducing valve, a controlvalve in said by-pass conduit means, electrical control means to actuatesaid control valve to open and closed positions, said control valve insaid open position admitting fluid to said chamber of a pressure higherthan that admitted to said chamber by said pressure reducing valve,exhaust means under con trol of said electrical control means andcommunicating with said chamber to momentarily exhaust fluid therefromto reduce the pressure therein as said control valve is being actuatedby said electrical control means from open to closed position, and saidelectrical control means comprising separately energized circuits toinsure that said exhaust means is open at a time when said control meansis closed, and manually operable contact means to separately energizesaid circuits.

References Cited in the file of this patent UNITED STATES PATENTS1,112,495 Turner Oct. 6, 1914 2,232,038 Stone Feb. 18, 1941 2,566,811Stevenson Sept. 4, 1951 2,611,846 Applegate .a Sept. 23, 1952 FOREIGNPATENTS 408,900 Great Britain Apr. 19, 1934

